IPv4 and IPv6 are two address systems for the same internet. Many home and mobile connections are dual-stack: you get both. FindMyIP shows one public address for the request to this site. That address may be IPv4 or IPv6; it does not test whether both families work. Neither is “fake.” They are parallel ways for packets to find you. Most people only notice when one stack works and the other does not.
See which family this request uses on What Is My IP. This is not the same question as public vs private IP — that post is about LAN ranges vs internet-facing addresses.
Why two versions exist
IPv4 uses 32-bit addresses (the familiar dotted form like 203.0.113.40). The pool is exhausted for practical purposes. Networks stretch it with NAT and shared IPv4 addressing through CGNAT.
IPv6 uses 128-bit addresses (colon-separated hex). It was built so devices can have abundant global addresses without everyone sharing one public IPv4 through layers of NAT.
The web did not flip a switch. Operators run both for years. Your phone, ISP, and favorite sites each enable stacks on their own timeline. That mismatch is where user-visible bugs come from.
What dual-stack means at home
On a dual-stack link:
- Your device can open connections over IPv4, IPv6, or whichever the OS prefers for that destination
- Your router may advertise both to the LAN
- A site with only A records (IPv4) is reached over IPv4; a site with AAAA may be tried over IPv6 first
So “what is my IP?” can honestly return two answers. One is your current IPv4 identity on the open internet. The other is your current IPv6 identity. Apps, CDNs, and logging systems may see either depending on the path that won.
Seeing IPv4 on FindMyIP establishes which family that request used. It does not establish that IPv6 is disabled or unavailable. A dual-stack connection can still use IPv4 for a particular destination.
How to read what FindMyIP shows
| Result on this site | What it shows | What remains unknown |
|---|---|---|
| An IPv4 address | This request reached the site with an IPv4 source | Whether IPv6 also works, or whether IPv4 is shared through CGNAT |
| An IPv6 address | This request reached the site with an IPv6 source | Whether IPv4 also works and whether every application uses this route |
| A different family on another checker | The requests used different paths or address families | Which path an untested app will use |
To assess dual-stack connectivity, use a diagnostic that makes separate IPv4-only and IPv6-only requests and records each outcome. The homepage’s single result cannot perform that comparison.
Paste either address into IP Lookup when you need ISP/org or coarse location for that specific address. Lookup is per address; the two stacks can land in slightly different labels.
Happy-eyeballs style problems (plain English)
Modern clients may race connection attempts across address families; RFC 8305 describes Happy Eyeballs behavior. When fallback is slow, pages feel “stuck” for a few seconds. When fallback fails, one browser or app looks broken while another works.
Clues it is a stack issue, not “the internet is down”:
- One device on the same Wi‑Fi fails; another works (different OS preference)
- Disabling IPv6 on the client (temporary test) fixes a site — that is a clue to investigate with your ISP or administrator, not proof of the exact fault; restore the setting after a controlled test
- Cellular works, home Wi‑Fi does not (or the reverse) — different ISP IPv6 deployments
You do not need to become a network engineer. You need to know which address family is in play before you reset everything.
Privacy and identity (keep this honest)
- Each public address is still a routing label. What a public IP can imply in general is covered in what your IP address reveals.
- IPv6 temporary addresses can change the interface identifier over time; the network prefix and other identifiers may still be linkable. That helps; it is not anonymity.
- A VPN typically replaces the public address(es) sites see with the VPN exit’s address(es). It does not redefine what IPv4 and IPv6 are. Turn the VPN on and reload What Is My IP if you want to confirm the visible identity changed.
No “best VPN” crown here — pick tools by logging policy, audits, and whether both address families behave the way you expect on your devices.
Quick checks when something is weird
- Load What Is My IP and note the single address and family used for that request.
- Retry the broken site on another network (phone hotspot vs home).
- Look up the address you care about in IP Lookup.
- If only some sites fail, ask whether those sites are IPv6-first; a broken IPv6 path is one possible cause, alongside DNS, routing or site configuration.
- Router firmware and ISP IPv6 toggles matter more than random Windows “winsock reset” rituals.
Check the family, then the path
IPv4 and IPv6 are parallel address systems, not rivals you must pick forever. Dual-stack means both can be “your IP” at once. When troubleshooting, read which family FindMyIP shows, test whether the failure follows that family, and treat VPN use as a change of public identity — not a rename of the protocols themselves.